Lubricating composition and method of making same



Patented Ot.'-17, 1939 UNITED sures.

Mm F-1cs 2,176,632 LUBRICATINg comrosrnon Ann rnon Paul La Frone Ransomvillc, N. 1., as

signer to E. i. do! out do lilemours & Gcmpany,

Wilmingto No Drawing. Ori

sinal 1937, Serial ,No. 161,628.

n, libel a corporation of Delaware pp ication An 8i),

Divided! and this airplication April 22, 1938, Serial No. ecs'nu e (oi. s'z-c) This invention relates to .sulfurized hydrocarbon products, to their preparation and to their use. as lubricant assistants in lubricating compositions.

5 This application is a division of'my co-pending application S. N. 161,628,-fi1ed August 30, 1937.

One object of this inyenticn isv to provide a m treme pressure lubricants and the like, Other objects will be apparent from the I description of my invention.

The above objects may be accomplished in accordance with my invention by heating a allm hydronaphthalene dimer with sulfur to form a sulfur reaction product of the dihydronaphthaleue dimer and, when it is desired to employ the product as a lubricant assistant, incorporating the product-into a lubricating oil. L

I have discovered that sulfur may be reacted with dihydronaphthalenc rs to give products which appear to be definite chemical compounds, although the nature of the reaction involved and the exact identity of the products formed are not entirely understood. 1 Thus, when 1,2-dihydr0naphthalene dimer is heated with sulfur, a reaction takes place to produce a light straw colored, clear liquid, the molecular weight of which varies with the amount of sulfur employed in the reaction and generally incremes as the sulfur content is increased. The reaction occurs substantially without hydrogen sulfide evolution, which distinguishes it from the reac tion of sulfur with aliphatic compounds. If an m excess of sulfur is employed, the sulfur in excess of that-amount required to mve a roduct containing about 11% of sulfur separates from the mixture upon cooling to room temperature. In-

- dications are that'a product'with a molecular- 45 weight of about 290 is obtained when the maximum. amount of sulfur isempioyed and the product is freed from unreactcd sulfur. r

The dihydronephthslene dimers which are suitable for preparing these sulfurized products are s the dimers of 1,4-dihydronaphthalene and 1,2

dihydronaphthalene. The dimer of IA-dihydronaphthalene may be prepared by the method of Scott and 7 Walker as described in their U. 5. Patent 2,055,708,,issued September 29, 1936. In

55 its crude state. as it is obtained by this method,

it is acolorless, or slightly yellow. viscous liquid at room temperature, distilling at 200-230" C. at

a pressure of 1-3 mm. of mercury. It has a pour point of about ill-15 (3., depending upon its degree of purity, and it solidifies to a hard brittle resin at a temperature of -10 to 0 C. When relatively pure, it has a-molecular weight of about 269. I

The dimer of LZ-dihydronaphthalene may be prepared by rearranging lA-dil' ydronaphthalene, to LZ-dihydronaphthalen 'by the method of Straus and Lemmel, Ber. 46: 232, and then polymerizlng the resulting product using sulfuric acid as the catalyst. The polymeriiation step is best carried out at 35-40 C. using a 10% concentraiion or 80% sulfuric acid. After about 5 to 3 hours at said temperature the mixture is heated to Gil-lt C. at which temperature the sulfuric acid. separates as a separate phase and may be drawn 0%. The dimerflcf l,2-dihydronaphthalene is a colorless or slightly yellow, viscous liquid which tends to crystallize slowly upon long stand- 'ing at room temperature. It hasla molecular weight of about 2% and distills' at about 210 C. at a pressure of 2 mm. of mercury. The product as prepared by the above method may contain some Le-dihydronaphthalenc dimer or monomeric dihydronaphthalene as an impurity, which is not objectionable for the present use.

I prefer to use the dimer of 1,2-dihydronaphthalene in the preparation of my new sulfurized product, since it is more easily obtainable in quantity. However, either dimer or mixtures of the two may be employed with excellent results in accordance with my invention. It is not necessa-ry that the dimer be employed in a pure condition since the crude products which are obtained by the methods referred to above are en.- tirely suitable for the present purpose.

The preparation of my new "sulfurized products is illustrated by the following example wherein LZ-dihydronaphthalene dimer is employed.

Example Four moles, 1040 grams, of 1,2-dihydronaph-- 1% hours after which it was cooled to room temperature. The product obtained was a clear, straw colored liquid which contained 10% of able, in order to reduce the fire hazard, to carry out the heating under an inert atmosphere, e. g., nitrogen.

In a run similar to' that described in the above example, twice the amount of sulfur, e. g., 2 atoms of sulfur per moleof dimer, was employed. It was found that only about one-half of the sulfur was retained in the product, the remainder separating from the reaction mixture upon cooling to room temperature. Apparently the sulfur forms a true compound, a monosulfide of the dihydronaphthalene dimer, having a molecular weight of about 290 when in purified condition. However,

especially when the reaction is not carried to completion, the crude product often will contain unreacted sulfur in solution.

My invention is not limited to the use of specific proportions of sulfur and dihydronaphthalene dimer in'preparing the sulfurized product. However, there is no advantage in employing sulfur in quantities greater than that required to give a product containing approximately 11% sulfur since sulfur in excess of this amount separates from the mixture. The use of reactants in the proportion of about 0.5 to 1 atom of sulfur to 1 mole of dihydronaphthalene dimer is generally preferred. When such proportions are used, the reaction product will contain about 5.8 to 11% of sulfur. vSmaller amounts of sulfurmay be'employed. However, since the product is'particularly useful as a source of sulfur, as will be described later, I prefer to use sulfur in the amounts above mentioned. 7

If an excess of sulfur is employed in the reaction, or if the reaction is not carried out to completion, sulfur which is unreacted but merely dissolved in the reaction product may be removed therefrom by treating the reaction mixture with a solvent, e. g., petroleum ether, in which sulfuris insoluble, whereby the unreacted sulfur is precipitated in solid form. The desired product may be separated from its solution in petroleum ether by distillation of the solvent. For most purposes,

the presen'ce'of impurities such as small amounts, of unreacted sulfur is not objectionable and for some uses may be an advantage and purification of the reaction mixture is not necessary.

The rate of reaction between the sulfur and the dihydronaphthalene dimer usually is not sufficiently rapid at temperatures substantially below 140 C. for practical purposes. I prefer to carry out the reaction at a temperature of 140470 C.

although higher temperatures may be employed. However, too high a temperature, e. g., temperatures at which hydrogen sulfide evolution becomes appreciable, should be avoided. In general,

a temperature of 140-170" C. isentirely satisfactory. r

The sulfurized products obtained from dihydro-.

naphthalene dimers in accordance with my in- ,vention are soluble in various organic solvents and particularly in the hydrocarbon solvents and their chlorinated products. Thus, they are sol- ,uble in petroleum and vegetable oils, the ordinary chlorinated hydrocarbon solvents, benzene, tolurequired. In particular, I have found thatthey i are well suited for use as lubricant assistants in lubricating compositions such as cutting oils, ex-

treme pressure lubricants, greases and the like. The products are particularly suitable for use in cutting oils since they not only appreciably 10 increase and improve the lubricating properties of the composition but also are easily miscible with the oil base to give clear, transparent light colored compositions which are generally desired in cutting oils. By means of my invention, relatively large amounts of sulfur may be added to the cutting oil without darkening the same. This is an important advantage since light colored, transparent oils are generally considered essential for cutting 011 applications. l'he amount of sufurized product, e. g., the reaction product of dimeric 1,2-dihydronaphthalene with sulfur, that need be added to the oil will vary withthe use for which the oil is intended. In general, I find it suitable to add the sulfurized product in such a quantity so as to give a sulfur content in the cutting oil composition of approximately 1 to 3%.

, cants. The sulfur reaction product may be added to give any desired sulfur content in the lubricating composition. In general, an amount sumcient to give 1 to 3% of sulfur is entirely satisfactory. Under such circumstances the load carrying capacity may be markedly increased.

My invention is not limited to the addition of the above described sulfurized products to oils of any particular viscosity nor to hydrocarbon oils since such compositions may be added to high or low viscosity mineral oils, including greases, as well as to oils of vegetable origin with excellent results. I

Because my products are readily soluble in oils of all types, including synthetic oils, they may be easily incorporated in any desired amount into cutting oils or extreme pressure lubricants and the like. If the composition into which my product is to be incorporated is relatively viscous at ordinary temperature, it is best to employ heat so as to facilitate thorough dispersion of the sulfurlzed product therein.

It is to be understood that that modification of my invention which relates to the use of the present sulfurized products as lubricant assistantsis not limited to particular concentrations mentioned above since the amount of sulfur desired in lubricating compositions may vary withinwide limits depending upon the particular use for which such compositions are desired. It will be apparent to those skilled in the preparation of such compositions that the-present sulfurized products may be employed to give any desired sulfur content within wide limits.

In the foregoing, I have described the preferred embodiments of my invention and various modifications thereof. It is to be understood that the present invention is not to be limited to such embodiments since they are merely illustrative and not restrictive of my invention. My invention is t? be limited only by the scope of the appended c aims.

compositions is used to designate oleaginous compositions which have lubricating properties lubricating oil is used to designate any solid or liquid substance which has recognized lubricating properties and includes substances of either vegetable or mineral origin. Cutting oils" are special lubricants used to lubricate and cool various cutting tools, in machine tools such as lathes, milling machines and the like.

I claim.

1. A lubricating composition comprising a lubricating oil and a reaction product of a dihydronaphthalene dimer and sulfur.

2. A lubricating composition comprising a lubricating oil and a reaction product of a dihydronaphthalene dimer and sulfur, said reaction product containing 5.8 to 11% sulfur.

3. A lubricating composition comprising a lubricating oil and a reaction product of 1,2-dihydronaphthalene dimer anchsulfur.

4. A lubricating composition comprising a'lubricating oil and a reaction product of 1,2-dihydronaphthalene dimer and sulfur, said reaction product containing 5.8 to 11% sulfur.

PAUL LAFRONE MAGILL. 

